This invention relates, in general, to a method of contacting a semiconductor die with a conductor and, more particularly, to a method of temporarily contacting a semiconductor die by means of a probe.
Generally, semiconductor integrated circuit manufacturers electrically test semiconductor die while they are still in wafer form using a testing procedure known as probing. Probing is performed by mating probes to corresponding bonding pads on the semiconductor die. Some of the probes convey input and output signals to and from the semiconductor die while others are coupled to power supply terminals which provide DC voltage signals to the semiconductor die.
Semiconductor die which have a high density of integrated devices also have a plurality of power bonding pads which are coupled to a power supply "power" terminal. Likewise, a plurality of reference bonding pads are included on the semiconductor die which are coupled to a power supply "reference" terminal. The plurality of bonding pads are contacted by probes, wherein at least one probe contacts each bonding pad. The probes contacting the power bonding pads are connected to the power supply "power" terminal, whereas the probes contacting the reference bonding pads are connected to the power supply "reference" terminal.
Using a plurality of bonding pads for coupling to the "power" and "reference" terminals decreases the current density through the probes by distributing the current through a larger area. A major drawback of probing is that it is difficult and tiptoe consuming to determine whether all of the "power" and "reference" bonding pads have been contacted by their corresponding probes. Although a probe test apparatus can readily determine if each signal probe has contacted its respective bonding pad, the same is not true for "power" and "reference" bonding pads because all the "power" probes are electrically connected together and all the "reference" probes are electrically connected. Once one of the "power" or "reference" probes contacts its corresponding bonding pad, it will appear as if all the "power" or "reference" probes have contacted their respective bonding pads.
Thus, if one of the "power" probes does not contact its corresponding bonding pad, the current that should have been supported by the noncontacting "power" probe is distributed to the remaining "power" probes. When several "power" probes do not contact their corresponding bonding pads, the current that they should have supported is redistributed to the "power" probes that do contact their corresponding bonding pads. A consequence of this redistribution is that the current supported by the remaining "power" probes is increased and may exceed the current density rating of the remaining "power" probes, resulting in the failure of these probes.
Accordingly, it would be advantageous to have a method of coupling the power supply output terminals with integrated circuit bonding pads that eliminates probe failures due to high current densities.